Detrimental electrochemical behavior caused by excessive high pressure on Li-ion pouch-type full cell
Jin Kyo Koo, Young‐Hoon Yun, Jae Kwon Seo, Sung Hoon Ha, Dong‐Won Kim, Junyoung Mun, Young‐Jun Kim
Abstract
Pressure on electrodes in cells is crucial for improving their active material density and electronic conductivity. A single-layer pouch cell (60 mAh) was fabricated to study the electrochemical effects of external pressures ranging from 0 to 3 MPa. The high-pressure cell at 3 MPa presented poor capacity retention owing to Li plating and pore-clogging on the graphite electrode. However, the optimized pressed cell did not hinder Li-ion transport in the graphite anode and underwent 200 cycles with 82 % capacity retention. External pressure impacts the contact between the electrodes and electrolyte; however, excessive pressure makes it difficult to supplement Li ions from the electrolyte into the graphite anode, resulting in increased polarization, electrolyte side reactions, and Li-metal deposition.